use Clang to C++-build the Python wheel

setup.py

@@ -28,10 +28,9 @@
     "win-arm64": "ARM64",
 }
 
-if platform.system() == "Darwin":
-    os.environ["CC"] = "clang"
-    os.environ["CXX"] = "clang"
-    os.environ["ARCHFLAGS"] = "-std=c++14"
+os.environ["CC"] = "clang"
+os.environ["CXX"] = "clang++"
+os.environ["CXXFLAGS"] = "-stdlib=libc++"
 
 BASE_DIR = os.path.realpath(os.path.dirname(__file__))
 MAKE_DOCS = os.environ.get("MAKE_DOCS")
@@ -76,6 +75,10 @@ def build_extension(self, ext):
             "-DBUILD_DOCS={}".format("ON" if MAKE_DOCS else "OFF"),
             "-DBUILD_EXAMPLE=OFF",
             "-DCMAKE_BUILD_TYPE={}".format(cfg),  # not used on MSVC, but no harm
+
+            # Add these lines:
+            "-DCMAKE_CXX_FLAGS=-stdlib=libc++",
+            "-DCMAKE_INSTALL_PREFIX=IOHexperimenter",
         ]
         build_args = []